Apparatus for forming articles of plastic material



OF PLASTIC MATERIALS 3 Sheets-Sheet 1 Filed Sept. 26, 1945 m M m w ,4.am a 6 9 rm 7 2 3 m 74 I. f H .7 3 5 3 a 3 M w l 7 0\ 3 5 3 1 2 w w 5 4x7 r 1. 3 2 4 0 N M 1 2 l a H 1 w y 4 mm (Z 3 2 3 2 9 V\- m Elwinih'dwli 3% V w wa March 29, 1949. E. A. HAWK 2,465,450

7 I APPARATUS FOR FORMING ARTICLES OF PLASTIC MATERIALS Filed Sept. 26,1945' 3 Sheets-Sheet 2 1 37 Elwin/4.116111% March 29, 1949. E. A. HAWKAPPARATUS FOR FORMING ARTICLES OF PLASTIC MATERIALS 3 Sheets-Sheet 3Patented Mar. 29, 1949 UNITED STATES PATENT OFFICE APPARATUS FOR FORMINGARTICLES OF PLASTIC. MATERIAL Elwin A. Hawk, East. Rochester, OhioApplication September 26, 1945, Serial No. 618,661

6 Claims. I

The invention relates to apparatus for forming articles of plasticmaterial, and particularly for forming dishes including plates andsaucers and the like from a ceramic body.

In usual methods of dish manufacture, each dish is formed on a plasterof Paris mold from a ceramic mixture made up p-redominanty of clay whichis passed through a filter press in a plastic condition. From the filterpress the plastic ceramic body is pugged in a pug mill, frequently undervacuum or subatmospheric pressure. The clay body is delivered from thepug mill in the shapeof a round column or roll which is delivered to. ajiggering; room where it is further processed on a batting out bench.

In the batting out process a small chunk of clay is pulled by hand fromthe roll and put on a plaster of Paris b ock and hit with a plaster ofParis mallet, until the chunk is flattened to a thin slab, which istaken from the block by hand and placed on a plaster of Paris mold.

The batting out process above described is the usual and older processand has been improved by various methods and apparatus from time totime. After the slab of the ceramic body is placed on the mold. the moldwith the slab is put on a rotary horizontal disk, and a rotary surfaceforming tool having the profile of the dish is passed over the slab at adistance from t e mold equal to the thickness of the dish or part. Theprofiled steel tool. which forms the bottom surface of the dish or part,removes excess of the plastic body'and forms a smooth profiled surfacewhich is usually the bottom of the dish or part. and this formingoperation is known as jiggering.

Usual methods of dish manufacture may be further summarized asincluding: first the pre paration of the ceramic body: second, thebatting out of a thin slab of the body on a mold; third, jiggering theslab on the mold; fourth, a ter the ,jiggering the formed dish is dried;and fifth. the dried formed disk is then fired.

In usual dish manufacture all of the steps are performed at atmosphericpressure except the pugging of the body which may be done atsubatmospheric pressure, such as by the use of the methods and apparatusset forth in my prior U. S. Patents Nos. 2,289,264 and 2,333,565.

The objects of the present invention include the provision of apparatusfor directly forming an article such as a dish or ceramic part from aplastic body such as a. ceramic. body without intermediate operations,as usuallycarried out.

Further objects of the present invention include the provision ofplastic and particularly ceramic prise the present invention and thenature of which is set forth in the. fo lowing general statement, andpreferred embodiments of which are set. forth in the following,description, and which are particularly and distinctly pointed out and tf h in the app nded claims o mi p rt hereof.

The nature of the improved methods of the present invention may bestated in general te ms as including forming on a mold subjected to r 5-atmospheric pressure. a successive series of thin layers of a plasticbody laid one upon the other so that because of the sub-atmosphericpressure the s ccessive thin layers of the plastic body knit togetherin. a h mo en ous mass as a fo article. In particular the b dy ay be aPl st ceramic body, and the formed article ay e a dish.

Furthermore. after the dish or other article is so formed on the mold bybuilding up successive.

thin layers of the plastic body. the dish or other article and the moldare preferably dried. together in a sub-atmospheric ressure.

Thenature of the improved ceramic forming apparatus for carrying out theimproved methods of the present invention may be stated in gen eralterms as including. improvements of the ap-. paratus set forth in mysaid prior U. S. Letters Patent No. 2,289,264 and 2,333,565. wherebyingredients for the. plastic body such as a plastic; ceramic body arefed directly int a sealed wall chamber, Where a column of' the ceramicbody is subjected to a sub-atmospheric pressure, and subsequent y aplurality of thin layers f the ceramic body are built up and preferab yprofiled by a rota-ting jiggering or forming tool on a mold, die, or thelike, the entire operation of building up the dish or other formedarticle being accomplished in a sub-atmospheric pressure by thepreferably rotating and profiling blade tool.

By way of example, preferred embodiments of" the improved plasticarticle forming apparatus of the present invention and of improved partsthereof are illustrated in the accompanying draw ings forming parthereof. in which Figure 1 is a vertical sectional view, as on thevertical axis of rotation of the jigger shaft and blade, of oneembodiment of the improved plastic article forming apparatus, theapparatus being shown empty of plastic material for purposes of clearlyillustrating all the parts;

Fig. 2, an enlarged view similar to Fig. 1 showing the lower portions ofthe improved apparatus in use during the forming of a plate on the moldby the rotating jigger blade operating on a descending mass of a ceramicbody;

Fig. 3, a view similar to Fig. 2 showing a plate completely formed onthe mold, and the mold separated from its sealing tubes;

Fig. 4, a horizontal sectional view as on line 4-4, Fig. 2; and

Fig. 5, a horizontal sectional view as on line -5, Fig. 3.

Similar numerals refer to similar parts throughout the drawings.

One embodiment of the improved plastic ma-. terial forming apparatus ofthe present invention is indicated generally by I0, and includes gassealed walls indicated generally by I I, which form a main chamber I2having an upper intake opening I3 and a lower discharge opening I4alined. with the upper intake opening I3.

Walls indicated generally by I5 form an ante- I chamber I5 above andcommunicating with the intake opening I3 of the main chamber [2. A sidewall of the antechamber I6 has a side intake opening II formed therein,and the border of the opening I1 is connected with the inner end of amaterial supply tube I8 having an outer flange I9 which may be connectedwith the discharge tube of a pug mill, not shown; whereby plasticmaterial such as a ceramic body in the pug mill and its discharge tubeconstitutes a gas seal for the supply tube I8, the antechamber I6, andthe communicating upper end of the main chamber I2, in a manner similarto that set forth in my U. S. Patent No. 2,333,565.

The lower discharge opening I4 of the main chamber I2 is provided withgas sealing means hereinafter set forth in detail, and within the gassealed main chamber I 2, a pressure treatment tube indicated generallyby an is mounted for rotation about an upwardly and downwardly extendingaxis indicated by the dot-dash line 2|, and which preferably and asshown is a vertical axis. I

The pressure treatment tube 20 is preferabl as shown cylindric, and itslength is preferably greater than its diameter, and the lon itud nalcenter axis of the tube 20 is preferably offset and parallel with the axs of rotation I8, and the tube 20 thus rotates about the eccentric axis2| with res ect to its own longitudinal center ax s, in a ma ner s milarto t at set forth in my said U. S. Patent No. 2,333.565.

The walls ind cated generally by II forming the main chamber I2 includeas s own, upper rectangu arly arranged side walls 22 having at theirupper ends inwardly extending reciangularly arran ed flanges 23. The topwall for the chamber I2 as shown is a separable rectangular p ate 24seated upon the upper faces of the flanges 23, and separably securedthereto as by headed screws 25, and the intake opening I3 is formed inthe too wall 24.

At the lower end of the rectangularly arranged chamber side walls 22 issecured a rectangular bottom wa l 26 having a preferably circularopening 21 formed therein which is concentric with the vertical axis 2I.From the lower face of the 49 31-3 of the tube 28.

4 chamber bottom wall 26 and about the opening 2! depends a preferablycylindrical tube 28.

A preferably cylindric intake tube 29 preferably extends from the intakeopening I3 of the main chamber I2 into the upper opening of the pressuretreatment tube 20, and as shown the intake tube 29 has an upperoutwardly extending flange 39 which is located within the antechamber I8and fits upon the upper face of the main chamber top wall 24 about theintake opening I3, and the intake tube flange 30 is secured to the topwall 24, as by headed screws 3|.

The walls I5 of the antechamber include side walls 32 having upperinwardly extending flanges 32-I upon the upper faces of which is seatedan antechamber top wall 33 which is separably secured to the flanges32-I, as by headed screws 34. At one side of the antechamber top wall 33there is formed an opening 35 which as shown is tapped, and has screwedtherein the threaded end of an evacuating tube 35 which extends to andcommunicatingly connects with a pump not shown, which for the particularpurposes of the present improvements is a vacuum pump.

The telescoping intake tube 29 and the upper end of the pressuretreatment tube 25 may have interposed therebetween material blocking andclearing means, not shown, such as set forth in my prior U. S. PatentNo. 2,333,565.

At the lower end of the depending tube 28, where the discharge openingI4 is located, the improved apparatus IIJ includes a separable moldmounting and sealing plate 31 having an outer annular upper face portion3'I-I, which may have a sealing washer 31-2 seated thereon, and eitherthe annular sealing face portion 3iI of the plate 31 or the washer 31-2of rubber or the like seated on the annular face portion 3II, separablyseal fits against the annular lower end sealing face As shown, thesealing plate 31 may be provided with an upwardly extending cylindricpilot flange 38 which fits in the lower end of the bore of the tube 29.

From the main chamber top wall 24 depend a plurality of preferablyvertical bars 39, and from the lower ends of the bars 39 depends, withinthe tube 28, a forming chamber and a mold seat tube 40. The pressuretreatment tube 29 is surrounded by the bars 39, and the lower end of thepressure treatment tube 29 extends into the tube 49. Longitudinallyspaced with respect to the axis 2|, the pressure treatment tube 28 haslocated and secured on its outside, a pair of track rings 4|, eachhaving formed therein an externally opening annular channel track 42.

There are at least three of the dep nding bars 39, and on each bar 39for each track ring 4I there is mounted a ball bearing 43 having anouter race ring 44 located within and rolling in the channel track 42 ofthe associated. track ring M. The mounting of each ball bearing 43 onits bar 39 is preferably eccentrically adjustable with respect to itsvert cal axis, as set forth in detail in my said U. S. Patent No.2,333,565.

Between the track rings 4|, there is mounted on the outside of thepressure treatment tube 29 a sprocket ring 45, and one of the mainchamber side walls 22 has a chain opening 49 formed therein which isenclosed by walls indicated generally by 41 forming a gas sealed motorcompartment 48 communicating through the chain opening 46 with the mainchamber I2. In the gas sealed motor compartment 48 there is mounted anelectric motor 49 having a vertical drive shaft 58 on the lower end ofwhich is secured a sprocket pinion" 51,- and aich ain belt 52 provides adriving:

connection between the motor sprocket pinion i and the-pressuretreatment tubesprocket ring'45.

For providing a gas sealed electrical connection or the motor with anexternal source of electric-power, side wall 5310i themotor'comparitment" 48 has two threaded apertures formed thereinin-e'ach of which is screw and seal mounted a usual internal combustionengine spark plug 5I,rand the insulated center electrode of each sparkplug is connected by a conductor 55 with one of the terminals of themotor winding within. the compartment 48. The external. binding: post:

51 of the center electrode of each spark plug is connected with oneconductor not shown of an electric power line including suitable controlswitches for starting: and stopping the motor 49-.

The top wall 33 of the antechamber i=8 has formed. therein a centralcircular opening 58- whose center coincides with the axis 2! and throughwhich extends an elongated bearing and blade mountingv tube 59, whichfits the circular opening. 58; "and has a gas sealed joint connectiontherewith as by an annular arc weld The tube 59- extends above the topWall 33 and also below the top wall 33', through the antechamber i6; theintaketube 29, and the pressure treatmenttubeZO.

The tube 59 is stationary and on its outside belowthe intake tube 29 andwithin the pressure treatment tubev 20 are mounted a plurality off'e'edscrew' blades 6| which are longitudinallyand' radially spaced fromeach other and each of: which has angled faces lying in a helix, Thepressure treatment tube is preferably lined with a cylindric' tubularscreen 62.

A ball bearing 63 is mounted at each end of the tube 59, one of the ballbearings 63 being at the upper end of the tube 59 above the antechambertop wall 33 and the other ball bearing 63 being at the lower end of thetube 59 within the pressure treatment tube 20.

A jigger shaft 64 extends through the bores of and: has a pressure fitwith the inner race rings of the ball bearings 63.

On the upper end of the jigger shaft B4 above the upper end of the tube59 the-re is secured a V pulley wheel 65. At one side of theantechamber' walls !5, there is mounted on the top face of the mainchamber top wall 24 amotor mounting bracket 66, on wh ch is mounted amotor 51 having a vert cal shaft 68 on the upper end of which is secureda V drive pulley B9, and a resilient V drive belt Ill drive connects thedrive pulley 69 and the V pulley wheel 65.

Walls indicated generally by H form with the top-wall 24 of the mainchamber l2 a gas sealed compartment 12 for the motor 61' and its driveconnection with the shaft 64. At the lower end of the jigger shaft 64immediately below the lower end of the pressure treatment tube 20 ajigger blade 13 extends radially above a mo d M. wh ch as illustrated isa plate mold. extending upwardly and mounted upon the sealing plate 31.The plate mold 14 has an outer conical peripheral portion 15 which sealsagainst the conical lower end face 16 of the tube 40. The top of themold 14 within the peripheral ring portion 15 has the conformation forone side face of the plate 11 which is iigger formed on the mold 14 bythe rotating ,iigger blade 73.

The motor 51 with n the comoartment lz is provided with a gas sealedelectrical connection with an external source of electric power throughthe side wall 18 of the compartment I2 by a iii) 6, pair of; usualinternal combustion engine spark plugs. Hi, and. theinsulated centerelectrode of each spark plug'19 is connected by conductor 8t with one ofthe terminals of the motor winding. The external binding post 8l--lofthei center electrode of each. spark plug [9 is connected with oneconductor not shown of an electricv power linedncluding suitable controlswitches for starting andstopping the motor 57. The evacuating tube 36'extends through a gas sealed joint 8-2 in one: of the walls of thecompartment 12,. asshown the top wall 83', and" within the com--par-tment I2 the evacuating tube 36 as shown has an inlet nipple 84 forevacuating the compartment 12.

In operating the improved plastic material forming apparatus lll thesupply tube l8 receives asealing plug, column of a ceramic body from thepug mill, not shown, with which the outer flange-- I9 is connected, andmaterial from the advanc ing column of the ceramic body drops throughthe antechamber 16, the intake tube 29 and intothepressure treatmenttube 20; which is rotated by the motr 56; The ceramic bodymaterialdropping into the rotating pressure treatment tube 29 piles uptherein and. forms an advancing. plug seal (Figs. 2, 3 and 4) at thebottom end of the tube 20 above the jigger blade 13. The" vacuum. pumpconnected with the evacuating tube 36 produces a sub-atmosphericpressure inthe: tubes. 28 and" sealed by the sealing plate 3-1 and mold14, respectively. The blades 6!- coacting with the rotating pressuretreatmenttube 20 cause the-advance of the homogenized,

' and degasified plug seal 85 atthe bottom of the pressure treatmenttube 20.

Operation of the motor 61 rotates the jigger shaft 64 and the jiggerblade 13, the jigger blade Ill-scraping off thin sectors of ceramic bodyfromthe advancing plug seal 85, as best shown in Fig. 2. These thinsectors of degasified ceramic body pile up in layers on the mold 1'4 andare worked by the rotating jigger blade 13 into the form of the plate11.

The upper portion of the jigger blade l3 opcrates as a scraper forscraping ofi or removing the thin sectors of ceramic body from theadvancing plug seal 85. The lower portion of the jigger blade 13 isprofiled for forming the layers of clay body on the mold 14.. It isobvious that the upper and lower portions of the one-piece jigger blade13 as shown, may be separatemembers.

By reason of the sub-atmospheric pressure inthe tube 40, the layers ofthe clay body worked by the jigger blade 13 on the mold M merge witheach other in a solid homogenized mass having the desired shape of theplate". After-'asuitablenumber. and relatively few rotations of thejigger blade 13. the formed plate I! is ready to be removed afterturning ed the vacuum pump connected with the evacuating tube 36 whichreleases the atmospheric pres-sure pushing against the sealing plate 31and holding it in position during the jiggering operation.

Fig. 5 shows the sealing plate 31 and the mold l4 thereon with theformed plate 11 of the ceramic body on the mo d 14, as they are beingseparated by being pulled downwardly from the tubes 40- and 28.

Preferably the entire apparatus In may be operated in an evacuated room.by workmen provided with suitable sources of oxygen supply. orotherwise, whereby the green plates 11 or other shapes formed by theapparatus l0 may be dried very rapidly by means of suitable heatsupplied into the evacuated room enclosing the apparatus H).

The embodiments of the improved apparatus and the method steps describedherein are by way of example, and the scope of the present invention isnot limited to the same or to the particular details thereof, but iscommensurate with any and all novel subject matter contained hereinwhich may at any time properly under the patent laws be set forth in theclaims hereof or originated herein, and the elements of any such claimsare intended to include their reasonable equivalents.

I claim:

1. Apparatus for forming articles of plastic material including wallsforming a gas sealed chamber, some of the walls including a downwardlyopening tube having a lower end and a sealing plate separably fittingand sealing the lower end of the tube, a mold within the chamber and onthe sealing plate, the mold having an upper face, a forming bladeoperatively mounted for movement in the chamber adjacent the upper faceof the mold, means for producing a sub-atmospheric pressure and gascontent within the chamber, and gas sealed means for introducing plasticmaterial into the chamber for being worked between the formin blade andthe mold.

2. Apparatus for formin articles of plastic material including wallsforming a gas sealed chamber, some of the walls including a downwardlyopening tube having a lower end and a sealing plate separably fittingand sealing the lower end of the tube, a mold within the chamber and onthe sealing plate, the mold having an upper face, a jiggering bladeoperatively mounted for rotation in the chamber adjacent the upper faceof the mold, means for'producing a subatmospheric pressure and gascontent within the chamber, and gas sealed means for introducing plasticmaterial into the chamber for being worked between the jiggering bladeand the mold.

3. Apparatus for forming articles of plastic material including wallsforming a gas sealed chamber, some of the walls including a downwardlyopening tube having a lower end and a sealing plate separably fittingand sealing the lower end of the tube, a mold within the chamber and onthe sealing plate, the mold having an upper face, a forming bladeoperatively mounted for movement in the chamber adjacent the upper faceof the mold, means for producing a sub-atmospheric pressure and gascontent within the chamber, gas sealed means for introducing a mass ofplastic material into the chamber, and means in the chamber for removinglayers of the plastic material from the mass so as to drop on the moldfor being worked between the forming blade and the mold.

4. Apparatus for forming articles of plastic material including wallsforming a gas sealed chamber, some of the walls including a downwardlyopening tube having a lower end and a sealing plate separably fittingand sealing the lower end of the tube, a mold within the chamber and onthe sealing plate, the mold having an upper face, a jiggering bladeoperatively mounted for rotation in the chamber adjacent the upper faceof the mold, means for producing a sub-atmospheric pressure and gascontent within the chamber, gas

sealed means for introducing a mass of plastic material into thechamber, and means in the chamber for removing layers of the plasticmaterial from the mass so as to drop on the mold for being workedbetween the jiggering blade and the mold.

5. Apparatus for forming articles of plastic material including wallsforming a gas sealed chamber, some of the walls including a tube havingan open end and a sealing plate separably fitting and sealing the openend of the tube, a mold within the chamber and on the sealing plate, themold having a forming face, a forming blade operatively mounted forrotation in the chamber adjacent the forming face of the mold, means forproducing a sub-atmospheric pressure and gas content within the chamber,and gas sealed means for introducing plastic material into the chamberfor being worked between the forming blade and the mold.

6. Apparatus for forming articles of plastic material including wallsforming a gas sealed chamber, some of the walls including a tube havingan open end and a sealing plate separably fitting and sealing the openend of the tube, a mold within the chamber and on the sealing plate, themold having a forming face, a forming blade operatively mounted forrotation in the chamber adjacent the forming face of the mold, means forproducing a sub-atmospheric pressure and gas content within the chamber,and gas sealed means for introducing a mass of plastic material into thechamber, and means in the chamber for removing layers of plasticmaterial from the mass for bein worked between the forming blade and themold.

ELWIN A. HAWK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 20,460 Jeffery Aug. 3, 19371,739,981 Miller Dec. 17, 1929 1,765,804 Preston June 24, 1930 2,013,026Bowling Sept. 3, 1935 2,165,671 Ward July 11, 1939 2,290,916 Smith et alJuly 28, 1942 2,301,939 Fischer Nov. 17, 1942

